Carrier to Noise Generator – CNG Series


  • The CNG-70/140 is a fully automated test instrument that sets and maintains a highly accurate ratio between a user-supplied carrier and internally generated White Gaussian noise. The instrument operates over a wide range of power levels. The modular design provides one or two totally independent channels covering 50 to 180 MHz. The instrument utilizes dBm’s proprietary microprocessor controlled attenuator with 0.015 dB resolution, so resolution uncertainty is less than 0.008 dB. Typical attenuator error is less than 0.02 dB over its entire frequency range and attenuation range.  The CNG corrects for noise density and signal level variations over frequency, and integrates the actual noise power over the user defined signal bandwidth. The carrier signal path is never interrupted.

    The CNG-1-800/2700 covers  800 to 2700 MHz, with the same accuracy as our 70/140 MHz units! In the CNG-1-800/2700, noise generation, attenuation, and power measurements are done at IF, so there is no degradation to ratio accuracy. Total noise bandwidth is 125 MHz, wide enough for virtually every application while still providing a high noise power spectral density.

    • C/N, C/No, Eb/No, and C/I modes
    • 1 or 2 independent RF channels
    • Frequency ranges up to 2.7 GHz


    Operating Mode C/N, C/No, Eb/No, C/I noise disabled, signal disabled
    Displayed Parameters Ratio, bit rate, duty cycle, frequency, average rate, averaging factor,
    output power, input power, delta input power
    Carrier Path RF Input Power:
    -50 dBm to +0 dBm
    RF Output Power:
    -110 dBm to +0 dBm*
    Input Duty Cycle:
    1% to 100%
    Nominal Gain:
    0 dB (@attenuation = 0 dB)
    Gain Resolution:
    1 dB
    Gain Flatness:
    <+/- 0.05 dB per 1.23 MHz bandwidth
    <+/- 0.2 dB per 40 MHz bandwidth
    Group Delay:
    +/- 0.20 ns per 40 MHz bandwidth
    Tracking Range:
    +/- 5 dB minimum
    Channel Isolation:
    >100 dB
    Residual Output Noise:
    <-149 dBm/Hz @ IF
    50 ohms
    1.5:1 maximum
    Type N female
    Noise Output Power:
    0 dBm to -110 dBm
    <+/- 0.2 dB per 40 MHz
    Amplitude Resolution:
    0.125 dB
    Crest Factor:
    18 dB minimum
    Measurement C/N Ratio Accuracy:
    +/- 0.2 dB RSS
    Averaging Factor:
    10 to 9999
    Averaging Rate:
    5 to 999Hz
    Absolute Accuracy:
    +/- 0.5 dB
    Control and Interface Local Interface:
    Front panel keypad and display
    Remote Interface:
    IEEE-488.2, TCP/IP
    10 states
    Primary Power Voltages:
    90-264 VAC autoranging
    48-66 Hz
    100 VA, maximum
    2A, slow-blow
    Physical Ambient Operating Temp:
    0° to 50° C
    17″ W x 5.25″ H x 21″ D